mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-26 02:39:48 +00:00
![Arnd Bergmann](/assets/img/avatar_default.png)
This prepares the removal of the big kernel lock from the file locking code. We still use the BKL as long as fs/lockd uses it and ceph might sleep, but we can flip the definition to a private spinlock as soon as that's done. All users outside of fs/lockd get converted to use lock_flocks() instead of lock_kernel() where appropriate. Based on an earlier patch to use a spinlock from Matthew Wilcox, who has attempted this a few times before, the earliest patch from over 10 years ago turned it into a semaphore, which ended up being slower than the BKL and was subsequently reverted. Someone should do some serious performance testing when this becomes a spinlock, since this has caused problems before. Using a spinlock should be at least as good as the BKL in theory, but who knows... Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Matthew Wilcox <willy@linux.intel.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Cc: "J. Bruce Fields" <bfields@fieldses.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Miklos Szeredi <mszeredi@suse.cz> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: John Kacur <jkacur@redhat.com> Cc: Sage Weil <sage@newdream.net> Cc: linux-kernel@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org
588 lines
16 KiB
C
588 lines
16 KiB
C
/* AFS file locking support
|
|
*
|
|
* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
|
|
* Written by David Howells (dhowells@redhat.com)
|
|
*
|
|
* This program is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU General Public License
|
|
* as published by the Free Software Foundation; either version
|
|
* 2 of the License, or (at your option) any later version.
|
|
*/
|
|
|
|
#include "internal.h"
|
|
|
|
#define AFS_LOCK_GRANTED 0
|
|
#define AFS_LOCK_PENDING 1
|
|
|
|
static void afs_fl_copy_lock(struct file_lock *new, struct file_lock *fl);
|
|
static void afs_fl_release_private(struct file_lock *fl);
|
|
|
|
static struct workqueue_struct *afs_lock_manager;
|
|
static DEFINE_MUTEX(afs_lock_manager_mutex);
|
|
|
|
static const struct file_lock_operations afs_lock_ops = {
|
|
.fl_copy_lock = afs_fl_copy_lock,
|
|
.fl_release_private = afs_fl_release_private,
|
|
};
|
|
|
|
/*
|
|
* initialise the lock manager thread if it isn't already running
|
|
*/
|
|
static int afs_init_lock_manager(void)
|
|
{
|
|
int ret;
|
|
|
|
ret = 0;
|
|
if (!afs_lock_manager) {
|
|
mutex_lock(&afs_lock_manager_mutex);
|
|
if (!afs_lock_manager) {
|
|
afs_lock_manager =
|
|
create_singlethread_workqueue("kafs_lockd");
|
|
if (!afs_lock_manager)
|
|
ret = -ENOMEM;
|
|
}
|
|
mutex_unlock(&afs_lock_manager_mutex);
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* destroy the lock manager thread if it's running
|
|
*/
|
|
void __exit afs_kill_lock_manager(void)
|
|
{
|
|
if (afs_lock_manager)
|
|
destroy_workqueue(afs_lock_manager);
|
|
}
|
|
|
|
/*
|
|
* if the callback is broken on this vnode, then the lock may now be available
|
|
*/
|
|
void afs_lock_may_be_available(struct afs_vnode *vnode)
|
|
{
|
|
_enter("{%x:%u}", vnode->fid.vid, vnode->fid.vnode);
|
|
|
|
queue_delayed_work(afs_lock_manager, &vnode->lock_work, 0);
|
|
}
|
|
|
|
/*
|
|
* the lock will time out in 5 minutes unless we extend it, so schedule
|
|
* extension in a bit less than that time
|
|
*/
|
|
static void afs_schedule_lock_extension(struct afs_vnode *vnode)
|
|
{
|
|
queue_delayed_work(afs_lock_manager, &vnode->lock_work,
|
|
AFS_LOCKWAIT * HZ / 2);
|
|
}
|
|
|
|
/*
|
|
* grant one or more locks (readlocks are allowed to jump the queue if the
|
|
* first lock in the queue is itself a readlock)
|
|
* - the caller must hold the vnode lock
|
|
*/
|
|
static void afs_grant_locks(struct afs_vnode *vnode, struct file_lock *fl)
|
|
{
|
|
struct file_lock *p, *_p;
|
|
|
|
list_move_tail(&fl->fl_u.afs.link, &vnode->granted_locks);
|
|
if (fl->fl_type == F_RDLCK) {
|
|
list_for_each_entry_safe(p, _p, &vnode->pending_locks,
|
|
fl_u.afs.link) {
|
|
if (p->fl_type == F_RDLCK) {
|
|
p->fl_u.afs.state = AFS_LOCK_GRANTED;
|
|
list_move_tail(&p->fl_u.afs.link,
|
|
&vnode->granted_locks);
|
|
wake_up(&p->fl_wait);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* do work for a lock, including:
|
|
* - probing for a lock we're waiting on but didn't get immediately
|
|
* - extending a lock that's close to timing out
|
|
*/
|
|
void afs_lock_work(struct work_struct *work)
|
|
{
|
|
struct afs_vnode *vnode =
|
|
container_of(work, struct afs_vnode, lock_work.work);
|
|
struct file_lock *fl;
|
|
afs_lock_type_t type;
|
|
struct key *key;
|
|
int ret;
|
|
|
|
_enter("{%x:%u}", vnode->fid.vid, vnode->fid.vnode);
|
|
|
|
spin_lock(&vnode->lock);
|
|
|
|
if (test_bit(AFS_VNODE_UNLOCKING, &vnode->flags)) {
|
|
_debug("unlock");
|
|
spin_unlock(&vnode->lock);
|
|
|
|
/* attempt to release the server lock; if it fails, we just
|
|
* wait 5 minutes and it'll time out anyway */
|
|
ret = afs_vnode_release_lock(vnode, vnode->unlock_key);
|
|
if (ret < 0)
|
|
printk(KERN_WARNING "AFS:"
|
|
" Failed to release lock on {%x:%x} error %d\n",
|
|
vnode->fid.vid, vnode->fid.vnode, ret);
|
|
|
|
spin_lock(&vnode->lock);
|
|
key_put(vnode->unlock_key);
|
|
vnode->unlock_key = NULL;
|
|
clear_bit(AFS_VNODE_UNLOCKING, &vnode->flags);
|
|
}
|
|
|
|
/* if we've got a lock, then it must be time to extend that lock as AFS
|
|
* locks time out after 5 minutes */
|
|
if (!list_empty(&vnode->granted_locks)) {
|
|
_debug("extend");
|
|
|
|
if (test_and_set_bit(AFS_VNODE_LOCKING, &vnode->flags))
|
|
BUG();
|
|
fl = list_entry(vnode->granted_locks.next,
|
|
struct file_lock, fl_u.afs.link);
|
|
key = key_get(fl->fl_file->private_data);
|
|
spin_unlock(&vnode->lock);
|
|
|
|
ret = afs_vnode_extend_lock(vnode, key);
|
|
clear_bit(AFS_VNODE_LOCKING, &vnode->flags);
|
|
key_put(key);
|
|
switch (ret) {
|
|
case 0:
|
|
afs_schedule_lock_extension(vnode);
|
|
break;
|
|
default:
|
|
/* ummm... we failed to extend the lock - retry
|
|
* extension shortly */
|
|
printk(KERN_WARNING "AFS:"
|
|
" Failed to extend lock on {%x:%x} error %d\n",
|
|
vnode->fid.vid, vnode->fid.vnode, ret);
|
|
queue_delayed_work(afs_lock_manager, &vnode->lock_work,
|
|
HZ * 10);
|
|
break;
|
|
}
|
|
_leave(" [extend]");
|
|
return;
|
|
}
|
|
|
|
/* if we don't have a granted lock, then we must've been called back by
|
|
* the server, and so if might be possible to get a lock we're
|
|
* currently waiting for */
|
|
if (!list_empty(&vnode->pending_locks)) {
|
|
_debug("get");
|
|
|
|
if (test_and_set_bit(AFS_VNODE_LOCKING, &vnode->flags))
|
|
BUG();
|
|
fl = list_entry(vnode->pending_locks.next,
|
|
struct file_lock, fl_u.afs.link);
|
|
key = key_get(fl->fl_file->private_data);
|
|
type = (fl->fl_type == F_RDLCK) ?
|
|
AFS_LOCK_READ : AFS_LOCK_WRITE;
|
|
spin_unlock(&vnode->lock);
|
|
|
|
ret = afs_vnode_set_lock(vnode, key, type);
|
|
clear_bit(AFS_VNODE_LOCKING, &vnode->flags);
|
|
switch (ret) {
|
|
case -EWOULDBLOCK:
|
|
_debug("blocked");
|
|
break;
|
|
case 0:
|
|
_debug("acquired");
|
|
if (type == AFS_LOCK_READ)
|
|
set_bit(AFS_VNODE_READLOCKED, &vnode->flags);
|
|
else
|
|
set_bit(AFS_VNODE_WRITELOCKED, &vnode->flags);
|
|
ret = AFS_LOCK_GRANTED;
|
|
default:
|
|
spin_lock(&vnode->lock);
|
|
/* the pending lock may have been withdrawn due to a
|
|
* signal */
|
|
if (list_entry(vnode->pending_locks.next,
|
|
struct file_lock, fl_u.afs.link) == fl) {
|
|
fl->fl_u.afs.state = ret;
|
|
if (ret == AFS_LOCK_GRANTED)
|
|
afs_grant_locks(vnode, fl);
|
|
else
|
|
list_del_init(&fl->fl_u.afs.link);
|
|
wake_up(&fl->fl_wait);
|
|
spin_unlock(&vnode->lock);
|
|
} else {
|
|
_debug("withdrawn");
|
|
clear_bit(AFS_VNODE_READLOCKED, &vnode->flags);
|
|
clear_bit(AFS_VNODE_WRITELOCKED, &vnode->flags);
|
|
spin_unlock(&vnode->lock);
|
|
afs_vnode_release_lock(vnode, key);
|
|
if (!list_empty(&vnode->pending_locks))
|
|
afs_lock_may_be_available(vnode);
|
|
}
|
|
break;
|
|
}
|
|
key_put(key);
|
|
_leave(" [pend]");
|
|
return;
|
|
}
|
|
|
|
/* looks like the lock request was withdrawn on a signal */
|
|
spin_unlock(&vnode->lock);
|
|
_leave(" [no locks]");
|
|
}
|
|
|
|
/*
|
|
* pass responsibility for the unlocking of a vnode on the server to the
|
|
* manager thread, lest a pending signal in the calling thread interrupt
|
|
* AF_RXRPC
|
|
* - the caller must hold the vnode lock
|
|
*/
|
|
static void afs_defer_unlock(struct afs_vnode *vnode, struct key *key)
|
|
{
|
|
cancel_delayed_work(&vnode->lock_work);
|
|
if (!test_and_clear_bit(AFS_VNODE_READLOCKED, &vnode->flags) &&
|
|
!test_and_clear_bit(AFS_VNODE_WRITELOCKED, &vnode->flags))
|
|
BUG();
|
|
if (test_and_set_bit(AFS_VNODE_UNLOCKING, &vnode->flags))
|
|
BUG();
|
|
vnode->unlock_key = key_get(key);
|
|
afs_lock_may_be_available(vnode);
|
|
}
|
|
|
|
/*
|
|
* request a lock on a file on the server
|
|
*/
|
|
static int afs_do_setlk(struct file *file, struct file_lock *fl)
|
|
{
|
|
struct afs_vnode *vnode = AFS_FS_I(file->f_mapping->host);
|
|
afs_lock_type_t type;
|
|
struct key *key = file->private_data;
|
|
int ret;
|
|
|
|
_enter("{%x:%u},%u", vnode->fid.vid, vnode->fid.vnode, fl->fl_type);
|
|
|
|
/* only whole-file locks are supported */
|
|
if (fl->fl_start != 0 || fl->fl_end != OFFSET_MAX)
|
|
return -EINVAL;
|
|
|
|
ret = afs_init_lock_manager();
|
|
if (ret < 0)
|
|
return ret;
|
|
|
|
fl->fl_ops = &afs_lock_ops;
|
|
INIT_LIST_HEAD(&fl->fl_u.afs.link);
|
|
fl->fl_u.afs.state = AFS_LOCK_PENDING;
|
|
|
|
type = (fl->fl_type == F_RDLCK) ? AFS_LOCK_READ : AFS_LOCK_WRITE;
|
|
|
|
lock_flocks();
|
|
|
|
/* make sure we've got a callback on this file and that our view of the
|
|
* data version is up to date */
|
|
ret = afs_vnode_fetch_status(vnode, NULL, key);
|
|
if (ret < 0)
|
|
goto error;
|
|
|
|
if (vnode->status.lock_count != 0 && !(fl->fl_flags & FL_SLEEP)) {
|
|
ret = -EAGAIN;
|
|
goto error;
|
|
}
|
|
|
|
spin_lock(&vnode->lock);
|
|
|
|
/* if we've already got a readlock on the server then we can instantly
|
|
* grant another readlock, irrespective of whether there are any
|
|
* pending writelocks */
|
|
if (type == AFS_LOCK_READ &&
|
|
vnode->flags & (1 << AFS_VNODE_READLOCKED)) {
|
|
_debug("instant readlock");
|
|
ASSERTCMP(vnode->flags &
|
|
((1 << AFS_VNODE_LOCKING) |
|
|
(1 << AFS_VNODE_WRITELOCKED)), ==, 0);
|
|
ASSERT(!list_empty(&vnode->granted_locks));
|
|
goto sharing_existing_lock;
|
|
}
|
|
|
|
/* if there's no-one else with a lock on this vnode, then we need to
|
|
* ask the server for a lock */
|
|
if (list_empty(&vnode->pending_locks) &&
|
|
list_empty(&vnode->granted_locks)) {
|
|
_debug("not locked");
|
|
ASSERTCMP(vnode->flags &
|
|
((1 << AFS_VNODE_LOCKING) |
|
|
(1 << AFS_VNODE_READLOCKED) |
|
|
(1 << AFS_VNODE_WRITELOCKED)), ==, 0);
|
|
list_add_tail(&fl->fl_u.afs.link, &vnode->pending_locks);
|
|
set_bit(AFS_VNODE_LOCKING, &vnode->flags);
|
|
spin_unlock(&vnode->lock);
|
|
|
|
ret = afs_vnode_set_lock(vnode, key, type);
|
|
clear_bit(AFS_VNODE_LOCKING, &vnode->flags);
|
|
switch (ret) {
|
|
case 0:
|
|
_debug("acquired");
|
|
goto acquired_server_lock;
|
|
case -EWOULDBLOCK:
|
|
_debug("would block");
|
|
spin_lock(&vnode->lock);
|
|
ASSERT(list_empty(&vnode->granted_locks));
|
|
ASSERTCMP(vnode->pending_locks.next, ==,
|
|
&fl->fl_u.afs.link);
|
|
goto wait;
|
|
default:
|
|
spin_lock(&vnode->lock);
|
|
list_del_init(&fl->fl_u.afs.link);
|
|
spin_unlock(&vnode->lock);
|
|
goto error;
|
|
}
|
|
}
|
|
|
|
/* otherwise, we need to wait for a local lock to become available */
|
|
_debug("wait local");
|
|
list_add_tail(&fl->fl_u.afs.link, &vnode->pending_locks);
|
|
wait:
|
|
if (!(fl->fl_flags & FL_SLEEP)) {
|
|
_debug("noblock");
|
|
ret = -EAGAIN;
|
|
goto abort_attempt;
|
|
}
|
|
spin_unlock(&vnode->lock);
|
|
|
|
/* now we need to sleep and wait for the lock manager thread to get the
|
|
* lock from the server */
|
|
_debug("sleep");
|
|
ret = wait_event_interruptible(fl->fl_wait,
|
|
fl->fl_u.afs.state <= AFS_LOCK_GRANTED);
|
|
if (fl->fl_u.afs.state <= AFS_LOCK_GRANTED) {
|
|
ret = fl->fl_u.afs.state;
|
|
if (ret < 0)
|
|
goto error;
|
|
spin_lock(&vnode->lock);
|
|
goto given_lock;
|
|
}
|
|
|
|
/* we were interrupted, but someone may still be in the throes of
|
|
* giving us the lock */
|
|
_debug("intr");
|
|
ASSERTCMP(ret, ==, -ERESTARTSYS);
|
|
|
|
spin_lock(&vnode->lock);
|
|
if (fl->fl_u.afs.state <= AFS_LOCK_GRANTED) {
|
|
ret = fl->fl_u.afs.state;
|
|
if (ret < 0) {
|
|
spin_unlock(&vnode->lock);
|
|
goto error;
|
|
}
|
|
goto given_lock;
|
|
}
|
|
|
|
abort_attempt:
|
|
/* we aren't going to get the lock, either because we're unwilling to
|
|
* wait, or because some signal happened */
|
|
_debug("abort");
|
|
if (list_empty(&vnode->granted_locks) &&
|
|
vnode->pending_locks.next == &fl->fl_u.afs.link) {
|
|
if (vnode->pending_locks.prev != &fl->fl_u.afs.link) {
|
|
/* kick the next pending lock into having a go */
|
|
list_del_init(&fl->fl_u.afs.link);
|
|
afs_lock_may_be_available(vnode);
|
|
}
|
|
} else {
|
|
list_del_init(&fl->fl_u.afs.link);
|
|
}
|
|
spin_unlock(&vnode->lock);
|
|
goto error;
|
|
|
|
acquired_server_lock:
|
|
/* we've acquired a server lock, but it needs to be renewed after 5
|
|
* mins */
|
|
spin_lock(&vnode->lock);
|
|
afs_schedule_lock_extension(vnode);
|
|
if (type == AFS_LOCK_READ)
|
|
set_bit(AFS_VNODE_READLOCKED, &vnode->flags);
|
|
else
|
|
set_bit(AFS_VNODE_WRITELOCKED, &vnode->flags);
|
|
sharing_existing_lock:
|
|
/* the lock has been granted as far as we're concerned... */
|
|
fl->fl_u.afs.state = AFS_LOCK_GRANTED;
|
|
list_move_tail(&fl->fl_u.afs.link, &vnode->granted_locks);
|
|
given_lock:
|
|
/* ... but we do still need to get the VFS's blessing */
|
|
ASSERT(!(vnode->flags & (1 << AFS_VNODE_LOCKING)));
|
|
ASSERT((vnode->flags & ((1 << AFS_VNODE_READLOCKED) |
|
|
(1 << AFS_VNODE_WRITELOCKED))) != 0);
|
|
ret = posix_lock_file(file, fl, NULL);
|
|
if (ret < 0)
|
|
goto vfs_rejected_lock;
|
|
spin_unlock(&vnode->lock);
|
|
|
|
/* again, make sure we've got a callback on this file and, again, make
|
|
* sure that our view of the data version is up to date (we ignore
|
|
* errors incurred here and deal with the consequences elsewhere) */
|
|
afs_vnode_fetch_status(vnode, NULL, key);
|
|
|
|
error:
|
|
unlock_flocks();
|
|
_leave(" = %d", ret);
|
|
return ret;
|
|
|
|
vfs_rejected_lock:
|
|
/* the VFS rejected the lock we just obtained, so we have to discard
|
|
* what we just got */
|
|
_debug("vfs refused %d", ret);
|
|
list_del_init(&fl->fl_u.afs.link);
|
|
if (list_empty(&vnode->granted_locks))
|
|
afs_defer_unlock(vnode, key);
|
|
goto abort_attempt;
|
|
}
|
|
|
|
/*
|
|
* unlock on a file on the server
|
|
*/
|
|
static int afs_do_unlk(struct file *file, struct file_lock *fl)
|
|
{
|
|
struct afs_vnode *vnode = AFS_FS_I(file->f_mapping->host);
|
|
struct key *key = file->private_data;
|
|
int ret;
|
|
|
|
_enter("{%x:%u},%u", vnode->fid.vid, vnode->fid.vnode, fl->fl_type);
|
|
|
|
/* only whole-file unlocks are supported */
|
|
if (fl->fl_start != 0 || fl->fl_end != OFFSET_MAX)
|
|
return -EINVAL;
|
|
|
|
fl->fl_ops = &afs_lock_ops;
|
|
INIT_LIST_HEAD(&fl->fl_u.afs.link);
|
|
fl->fl_u.afs.state = AFS_LOCK_PENDING;
|
|
|
|
spin_lock(&vnode->lock);
|
|
ret = posix_lock_file(file, fl, NULL);
|
|
if (ret < 0) {
|
|
spin_unlock(&vnode->lock);
|
|
_leave(" = %d [vfs]", ret);
|
|
return ret;
|
|
}
|
|
|
|
/* discard the server lock only if all granted locks are gone */
|
|
if (list_empty(&vnode->granted_locks))
|
|
afs_defer_unlock(vnode, key);
|
|
spin_unlock(&vnode->lock);
|
|
_leave(" = 0");
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* return information about a lock we currently hold, if indeed we hold one
|
|
*/
|
|
static int afs_do_getlk(struct file *file, struct file_lock *fl)
|
|
{
|
|
struct afs_vnode *vnode = AFS_FS_I(file->f_mapping->host);
|
|
struct key *key = file->private_data;
|
|
int ret, lock_count;
|
|
|
|
_enter("");
|
|
|
|
fl->fl_type = F_UNLCK;
|
|
|
|
mutex_lock(&vnode->vfs_inode.i_mutex);
|
|
|
|
/* check local lock records first */
|
|
ret = 0;
|
|
posix_test_lock(file, fl);
|
|
if (fl->fl_type == F_UNLCK) {
|
|
/* no local locks; consult the server */
|
|
ret = afs_vnode_fetch_status(vnode, NULL, key);
|
|
if (ret < 0)
|
|
goto error;
|
|
lock_count = vnode->status.lock_count;
|
|
if (lock_count) {
|
|
if (lock_count > 0)
|
|
fl->fl_type = F_RDLCK;
|
|
else
|
|
fl->fl_type = F_WRLCK;
|
|
fl->fl_start = 0;
|
|
fl->fl_end = OFFSET_MAX;
|
|
}
|
|
}
|
|
|
|
error:
|
|
mutex_unlock(&vnode->vfs_inode.i_mutex);
|
|
_leave(" = %d [%hd]", ret, fl->fl_type);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* manage POSIX locks on a file
|
|
*/
|
|
int afs_lock(struct file *file, int cmd, struct file_lock *fl)
|
|
{
|
|
struct afs_vnode *vnode = AFS_FS_I(file->f_dentry->d_inode);
|
|
|
|
_enter("{%x:%u},%d,{t=%x,fl=%x,r=%Ld:%Ld}",
|
|
vnode->fid.vid, vnode->fid.vnode, cmd,
|
|
fl->fl_type, fl->fl_flags,
|
|
(long long) fl->fl_start, (long long) fl->fl_end);
|
|
|
|
/* AFS doesn't support mandatory locks */
|
|
if (__mandatory_lock(&vnode->vfs_inode) && fl->fl_type != F_UNLCK)
|
|
return -ENOLCK;
|
|
|
|
if (IS_GETLK(cmd))
|
|
return afs_do_getlk(file, fl);
|
|
if (fl->fl_type == F_UNLCK)
|
|
return afs_do_unlk(file, fl);
|
|
return afs_do_setlk(file, fl);
|
|
}
|
|
|
|
/*
|
|
* manage FLOCK locks on a file
|
|
*/
|
|
int afs_flock(struct file *file, int cmd, struct file_lock *fl)
|
|
{
|
|
struct afs_vnode *vnode = AFS_FS_I(file->f_dentry->d_inode);
|
|
|
|
_enter("{%x:%u},%d,{t=%x,fl=%x}",
|
|
vnode->fid.vid, vnode->fid.vnode, cmd,
|
|
fl->fl_type, fl->fl_flags);
|
|
|
|
/*
|
|
* No BSD flocks over NFS allowed.
|
|
* Note: we could try to fake a POSIX lock request here by
|
|
* using ((u32) filp | 0x80000000) or some such as the pid.
|
|
* Not sure whether that would be unique, though, or whether
|
|
* that would break in other places.
|
|
*/
|
|
if (!(fl->fl_flags & FL_FLOCK))
|
|
return -ENOLCK;
|
|
|
|
/* we're simulating flock() locks using posix locks on the server */
|
|
fl->fl_owner = (fl_owner_t) file;
|
|
fl->fl_start = 0;
|
|
fl->fl_end = OFFSET_MAX;
|
|
|
|
if (fl->fl_type == F_UNLCK)
|
|
return afs_do_unlk(file, fl);
|
|
return afs_do_setlk(file, fl);
|
|
}
|
|
|
|
/*
|
|
* the POSIX lock management core VFS code copies the lock record and adds the
|
|
* copy into its own list, so we need to add that copy to the vnode's lock
|
|
* queue in the same place as the original (which will be deleted shortly
|
|
* after)
|
|
*/
|
|
static void afs_fl_copy_lock(struct file_lock *new, struct file_lock *fl)
|
|
{
|
|
_enter("");
|
|
|
|
list_add(&new->fl_u.afs.link, &fl->fl_u.afs.link);
|
|
}
|
|
|
|
/*
|
|
* need to remove this lock from the vnode queue when it's removed from the
|
|
* VFS's list
|
|
*/
|
|
static void afs_fl_release_private(struct file_lock *fl)
|
|
{
|
|
_enter("");
|
|
|
|
list_del_init(&fl->fl_u.afs.link);
|
|
}
|